B2 Visa- immigration law violation

When I fill the I-160, Do I answer yes or no for the following question????

Have you ever been unlawfully present, overstayed the amount of time granted by an immigration official or otherwise violated the terms of a U.S. visa?

Situation

I applied B2 extension back in 2007 for my mom when she was in the states. Her B2 extension was pending when it was outside the 6 month stay time. 5 days later, she got the denial notice. She bought a ticket back to China within one week. She came back after one month in China and came back after another 5 months.

I called USCIS and the call center people told me that there was a grace period for 30 days.

My mom is going to apply visa this June.

Thanks